docs: def edit_custom_examples(program, config):
      """
      Edit custom examples for the given program, creating the file if it does
      not exist.
      """
      if (not config.custom_dir) or (not os.path.exists(config.custom_dir)):
          _inform_cannot_edit_no_custom_dir()
          return
  
      # resolve aliases
      resolved_program = get_resolved_program(program, config)
      custom_file_paths = get_file_paths_for_program(
          resolved_program,
          config.custom_dir
      )
  
      if (len(custom_file_paths) > 0):
          path_to_edit = custom_file_paths[0]
      else:
          # A new file.
          path_to_edit = os.path.join(config.custom_dir, resolved_program + '.md')
  
      # Edit the first. Handles the base case.
      subprocess.call([config.editor_cmd, path_to_edit])